Storage stool



FIG. 1 is a top perspective view of a storage stool;

FIG. 2 is a bottom perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a top view thereof; and,

FIG. 6 is a bottom view thereof.

The broken lines in the drawings depict features of the storage stool that form no part of the claimed invention. 

CLAIM The ornamental design for a storage stool, as shown and described. 